public virtual DataType ProcessIdentExpression(IdentExpressionAst identExpression)
{
var name = identExpression.IdentifierToken.Value;
if (!SymbolScope.FindSymbolDeep(name, out Symbol symbol))
{
throw new SemanticException($"Symbol {name} not exist");
}
if (!(symbol is VariableSymbol variableSymbol))
{
throw new SemanticException($"Symbol {name} is not const/var");
}
// All check ok
if (CodeGenerationEnabled)
{
// load-variable-addr
if (variableSymbol.IsGlobal)
{
var id = variableSymbol.GlobalVariableBuilder.Id;
ExpressionBucket.Add(new object[] { "globa", id });
}
else
{
if (variableSymbol.LocalLocation.IsArgument)
{
var id = variableSymbol.LocalLocation.Id;
if (CurrentFunction.ReturnType != DataType.Void)
{
id++;// because arg0 is ret val
}
var instruction = Instruction.Pack("arga", id);
instruction.Comment = variableSymbol.Name + " (ident-expr)";
ExpressionBucket.Add(instruction);
}
else
{
// 局部变量
var id = variableSymbol.LocalLocation.Id;
ExpressionBucket.Add(new object[] { "loca", id });
}
}
// de-reference
ExpressionBucket.Add(Instruction.Pack("load.64"));
}
return(variableSymbol.Type);
}
public void ProcessFunction(FunctionAst functionAst)
{
Guard.Against.Null(functionAst, nameof(functionAst));
if (SymbolScope.FindSymbolDeep(functionAst.Name.Value, out Symbol symbol))
{
throw new SemanticException($"Symbol already exist: {symbol.Name}, {symbol.GetType()}");
}
if (!new[] { "int", "double", "void" }.Contains(functionAst.ReturnType.Value))
{
throw new SemanticException($"Bad returning type: {functionAst.ReturnType.Value}");
}
var returnType = DataTypeHelper.ParseIntDoubleVoid(functionAst.ReturnType.Value);
// Add function to scope
var paramTypeList = new List <DataType>();
if (functionAst.HasParams)
{
foreach (var parameter in functionAst.FunctionParamList.FunctionParams)
{
var paramType = parameter.Type.Value switch
{
"int" => DataType.Long,
"double" => DataType.Double,
_ => throw new SemanticException($"Bad param type: {parameter.Type.Value}")
};
paramTypeList.Add(paramType);
}
}
var functionSymbol = new FunctionSymbol(functionAst.Name.Value, returnType, paramTypeList);
SymbolScope.AddSymbol(functionSymbol);
// register function
if (CodeGenerationEnabled)
{
GlobalBuilder.RegisterFunction(functionSymbol);
}
// Create scope
SymbolScope = SymbolScope.CreateChildScope();
// for testing
functionSymbol.BodyBlockScope = SymbolScope;
EnterFunctionDefination(functionSymbol);
{
// register params
if (functionAst.HasParams)
{
foreach (var parameter in functionAst.FunctionParamList.FunctionParams)
{
var paramType = parameter.Type.Value switch
{
"int" => DataType.Long,
"double" => DataType.Double,
_ => throw new SemanticException($"Bad param type: {parameter.Type.Value}")
};
var name = parameter.Name.Value;
if (SymbolScope.FindSymbolShallow(name, out Symbol _))
{
throw new SemanticException($"Exist symbol: {name}");
}
// Add to scope
var argSymbol = new VariableSymbol(name, false, parameter.IsConstant, paramType);
SymbolScope.AddSymbol(argSymbol);
if (CodeGenerationEnabled)
{
CurrentFunction.Builder.RegisterArgument(argSymbol);
}
}
}
var canReturn = ProcessBlockStatement(functionAst.BodyBlock, suppressNewScopeCreation: true);
if (!canReturn && ReturnCheckEnabled && returnType != DataType.Void)
{
throw new SemanticException($"Cannot leave function {functionAst.Name.Value}");
}
// implecit void returning
if (CodeGenerationEnabled && returnType == DataType.Void)
{
CurrentFunction.Builder.Bucket.Add(new Instructions.Instruction("ret"));
}
}
LeaveFunctionDefination();
SymbolScope = SymbolScope.ParentScope;
}
public virtual DataType ProcessAssignExpression(AssignExpressionAst assignExpression)
{
// IDENT '=' expr
// IDENT 是可以赋值的变量，expr是int或者double
var name = assignExpression.Identifier.Value;
if (!SymbolScope.FindSymbolDeep(assignExpression.Identifier.Value, out Symbol symbol))
{
throw new SemanticException($"Symbol name '{name}' not found");
}
if (!(symbol is VariableSymbol variableSymbol))
{
throw new SemanticException($"Symbol '{name}' is function symbol, cannot assign value");
}
if (variableSymbol.IsConstant)
{
throw new SemanticException($"Symbol '{name}' is constant, cannot assign value");
}
var valueType = ProcessExpression(assignExpression.Expression);
if (valueType != variableSymbol.Type)
{
throw new SemanticException(
$"Variable '{name}' is type '{variableSymbol.Type}', but expression is '{valueType}'");
}
var valueExpressionCode = ExpressionBucket.Pop();
// All check ok
if (CodeGenerationEnabled)
{
// load-variable-addr
if (variableSymbol.IsGlobal)
{
var id = variableSymbol.GlobalVariableBuilder.Id;
ExpressionBucket.Add(new object[] { "globa", id });
}
else
{
if (variableSymbol.LocalLocation.IsArgument)
{
// 函数参数 (+1)
var id = variableSymbol.LocalLocation.Id;
if (CurrentFunction.ReturnType != DataType.Void)
{
id++;
}
var instruction = Instruction.Pack("arga", id);
instruction.Comment = variableSymbol.Name + " call-arg";
ExpressionBucket.Add(instruction);
}
else
{
// 局部变量
var id = variableSymbol.LocalLocation.Id;
ExpressionBucket.Add(new object[] { "loca", id });
}
}
// value-expr
ExpressionBucket.AddRange(valueExpressionCode);
// store.64
ExpressionBucket.Add(new Instruction("store.64"));
}
return(DataType.Void);
}
public virtual DataType ProcessCallExpression(CallExpressionAst callExpression)
{
var name = callExpression.Identifier.Value;
if (!SymbolScope.FindSymbolDeep(name, out Symbol symbol))
{
throw new SemanticException($"Symbol name '{name}' not found");
}
if (!(symbol is FunctionSymbol functionSymbol))
{
throw new SemanticException($"Symbol '{name}' is not function, cannot call.");
}
// ret-space: 如果是stdlibs，不需要预留空间。如果是返回void的，也不用。
if (CodeGenerationEnabled && !IsStdLibCall(functionSymbol.Name) && functionSymbol.ReturnType != DataType.Void)
{
ExpressionBucket.Add(new object[] { "push", (long)0 });
}
var needCount = functionSymbol.ParamTypes.Count;
var providedCount = callExpression.HasParams ? callExpression.ParamList.Parameters.Count : 0;
if (needCount != providedCount)
{
throw new SemanticException($"Function '{name}' needs {needCount} param(s)," +
$"but provided {providedCount} param(s)");
}
// Now, 0:0 or n:n. Check the types when n:n
if (needCount != 0)
{
var providedTypes = new List <DataType>();
foreach (var parameter in callExpression.ParamList.Parameters)
{
var expressionType = ProcessExpression(parameter);
providedTypes.Add(expressionType);
}
Debug.Assert(functionSymbol.ParamTypes.Count == providedTypes.Count);
if (!functionSymbol.IsParamTypeMatch(providedTypes))
{
throw new SemanticException($"Call to function '{name}' cannot match param types");
}
}
// call func id
if (CodeGenerationEnabled)
{
if (!IsStdLibCall(functionSymbol.Name))
{
var funcId = functionSymbol.Builder.Id;
ExpressionBucket.Add(Instruction.Pack("call", funcId));
}
else
{
// stdlib calls
var opcode = StdLibReference[functionSymbol.Name];
Debug.Assert(opcode != null);
ExpressionBucket.Add(new Instruction(opcode));
}
}
return(functionSymbol.ReturnType);
}